Variable length boom extension



Dec. 4, 1956 R. D. KAUFFMAN VARIABLE LENGTH BOOM EXTENSION Fild May 9, 1955 2 sheets shee t 1 mm mm nvmyrog Roy D. Kauffmon ll? i Dec. 4,1956 D. KAUFFMAN 2,772,790

VARIABLE LENGTH BOOM EXTENSION Filed May 9, 195@ 2heets-fgeet 2 FIG.3. 42 7 6 69 Y 7' 5. fi n '4 36 I5 44 39 five/7 for Roy D. Kuuffmon fT Yi United States Patent VARIABLE LENGTH BOOM EXTENSION Roy D. Kaulfman, Washington, D. C.

Application May 9, 1955, Serial No. 506,740

7 Claims. (Cl. 212-144) This invention relates to boom constructions generally and pertains more particularly to a rapidly constructed variable length boom extension for use in conjunction with standard and conventional booms.

The exact length of boom necessary, for handling a particular job is seldom known and it frequently occurs in practical usage of booms that the boom must be lengthened to perform the necessary work aft-er the crane structure has been moved to the site of operation. The time consumed in lengthening a boom is quite considerable and entails a great deal of work and may involve several men. It is, therefore, a primary object of this invention to provide an extension assembly for use in conjunction with a conventional boom structure so that the effective length of the boom may be lengthened rapidly and with a minimum of manpower.

It is another object of this invention to provide a variable length boom extension which is easily assembled on a conventional type of boom by one man and which requires but a few minutes of time to completely and properly assemble on the boom to vary the effective length thereof in accordance with the requirements of a particular operation.

Still another object of this invention is to provide an improved form of boom extension which is made up of several separable component parts, which separability not only reduces the weight of any one component to within limits which one man can handle but which also permits the use of one. of several interchangeable components so that the effective length of the extension may be varied at will.

Still another object of this invention is to provide an improved form of boom extension which is not only light in weight so as to be manipulable by one man but which is also so constructed as to provide a maximum of rigidity and prevent swing or buckling of the boom extension during use.

A further object of this invention is to provide an improved boom extension which includes an extension assembly composed of three separable sections each of which is easily manipulated by a single man, and a support assembly operatively connected to the extension assembly for maintaining the extension assembly sections in proper relationship on an associated boom, the support assembly also serving to carry a guide pulley member over which the boom cable is trained.

As this invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, the present embodiment is therefore illustrative and not restrictive, since the scope of the invention is defined by the appended claims rather than by the description preceding them, and all changes that fall within the metes and bounds of the claims or that form their functional as well as conjointly cooperative equivalents, are therefore intended to be embraced by those claims.

In the drawings:

Fig. 1 is a side elevational view showing the improved 2,772,790 Patented Dec. 4, 1956 extension secured to an associated boom of conventional design and illustrating the manner in which the various component parts are related when the device is completely assembled;

Fig. 2 is a longitudinal section taken through the base section of the extension assembly illustrating details of its construction and showing the manner in which the intermediate section is associated therewith;

Fig. 3 is a longitudinal section taken through the end section of the extension assembly and showing details of its internal construction as well as the manner in which it is related to the intermediate section;

Fig. 4 is a front elevational view of the support assembly;

Fig. 5 is an enlarged sectional view showing the upper end of the support assembly and showing details of the anchor pin member; and

Fig. 6 is a perspective view of the completely assembled boom extension.

Referring now more particularly to the drawings and at this point most particularly to Fig. 1 thereof, the reference numeral 10 indicates generally the free end of the end section of a conventional boom, the construction of which forms no part of this invention. Pivotally secured by means of the pin member 11 to the forward end of this conventional boom is an extension assembly which is indicated generally by the reference character 12 which is composed of three separable component parts or sections 13, 14 and 15. For the purpose of description, the section or component part 13 will be designated as the base section whereas the section 1 4 will be designated as the intermediate section and the part 15 will be designated as the end section.

Operatively associated with the extension assembly 12 and connected thereto by means of a pin member 16 is the support or stabilizing assembly which is indicated generally by the reference character 17 and which is shown most clearly in Fig. 4.

The boom 10 which may be of any conventional design is provided on either side thereof with a pair of lug members'18 and 19 as will be seen most clearly in Figs. 2 and 6. These lug members may be attached to the boom 10 by any suitable means such as welding or the like and their forward end-s project forwardly of the boom in the manner shown to provide convenient means to which the extension assembly is attached. In regard to this, it will be seen most clearly from Fig. 2 that the base section 13 is comprised of a pair of mutually convergent arms 20 and 21 which have angulated rearward end portions 22 and 23 disposed in parallel relation and disposed a sufficient distance apart to straddle the lug members 18 and 19 in the manner shown. The end portions 22 and 23 are apertured as are the lug members 18 and 19 to permit a pin member 24 to be passed therethrough so as to securely attach the extension assembly 12 and more particularly the base section 13 thereof to the lugs 13 and 19. Of course, suitable cotter pins such as those indicated at 2'5 and 26 may be associated with the pin 24 for the purpose of retaining the same within the various apertures of the lugs and end portions 22 and 2-3.

The forward ends of the arms 20 and 21 terminate in the angulated portions 27 and 28 which like the opposite end portions 22 and 23 are disposed in parallel relationship. Disposed between these end portions 27 and 28 is a tubular body member 29 whose longitudinal center line is parallel to the elongate arms 20 and 21 and the angulated portions 27 and 28 are rigidly attached thereto as by the welding 30. The rearward end 31 of the tubular member 29 extends to a point substantially midway between the opposite ends of the arms 20 and 21 and a stop member indicated generally by the reference character 32 is rigidly attached between the arms at this bers 20 and 21 at a point substantially midway of their opposite ends to provide a very rigid assembly and prevent side sway of the bottom extension when in use. Furthermore, the stop member 32 serves as a further connection between the arm members 20 and 21 and the tubular member 29 with the points of interconnectiontherebetween widely spaced such that the tubular member 29 is very effectively and rigidly attached to the arm members while at the same time the overall weight of the base section is maintained within reasonable limits. The manner of interconnection between the stop member on the one hand and the arms 20 and 21 as well as the tubular member 29 is preferably by means of welding.

The stop member 32 may take any desired form but it is preferred that it be both rigid and light weight as, for example, by means of a structure substantially as shown which is of channel shape configuration and which includes a web portion 33 which forms the abutting surface for the intermediate section 14 and the upstanding leg portions 34 and 35.

It will be noted that the base section 13 is attached to the boom at two widely spaced points by virtue of the wide spacing between the angulated end portions 22 and 23 of the arms. This serves to provide a very substantial support for the base section 13 and consequently the extension assembly and reduces side sway of the extension member to a minimum and obviates from a practical standpoint the chance of the extension assembly buckling. This widely spaced connection between the base section and the boom taken in conjunction with the provision of the multiple purpose stop member 32 provides very rigid support for the extension assembly as a whole.

The end section is indicated most clearly in Fig. 3 and will be seen to consist of an elongate tubular member 36 which is provided with a longitudinally extending notch 37 extending inwardly from its forward free end. A pair of plate members 38 and 39 are disposed in spaced relation within the notch 37 and contacting the opposite sides thereof whereat the plates are rigidly secured as by welding to the forward free end of the tubular member 36. The plates each have dependmg lower edge portions as indicated by the numerals 40 and 41 which as shown are preferably arcuated in the manner shown most clearly in Figs. 1 and 6. Disposed within the tubular member 36 and rigidly secured to the inner edges of the plates 38 and 39 is a stop plate 42 which serves as an abutment means against which the intermediate section 14 bottoms. To prevent spreading or collapse of the notched portion of the tubular body 36, a reinforcing strap 43 is interposed between the forward free edges of the plate members 40 and 41 and is rigidly attached thereto by suitable means such as welding. The opposite side walls of the member 36 and the plates 38 and 39 are all provided with registering apertures for the reception of the pivot pin member 44 which is projected therethrough and journaled on this pin within the notch 37 and between the plates 38 and 39 is a pulley or sheave 45 over which the boom cable 46 is trained. For a purpose which will be presently apparent, the pin 44 is of considerable length so that it projects a substantial distance beyond each side of the tubular member 36. v

The intermediate section which serves to space the two sections 13 and 15 apart a predetermined distance in accordance with the desired overall effective length of the boom extensionis preferably in the form of an elongate tube and there are preferably provided several such intermediate sections of varying length so as to accommodate for several desired extension lengths. Thus, it will be apparent that the intermediate section 14 is interchangeable and anyone of several different lengths thereof may be utilized with the base and end sections 13 and 15 to vary the spacing therebetween and consequently the effective length of the boom extension. The internal diameters of the members 29 and 36 are preferably substantially identical and it is preferred that the intermediate section 14 form a fairly snug fit therewithin so as to minimize lost motion between the parts but the fit is not sufiiciently tight as to prevent ready removal of the intermediate section from either the base or end sections.

it will now be evident that the formation of the extension assembly 12 from the three separable sections 13, 14 and 15 serves not only to permit the use of varying lengths of the intermediate section 14 but it also permits one part at a time to be handled by the man assembling the unit so that at no time will he have to manipulate the weight of the entire assemblage. Conse quently, it is possible for one man alone to assemble the extension assembly and to this end it is merely neces sary to first position the base section 13 so that the pin 11 may be properly placed to connect the base section to the boom is and, thereafter, the intermediate and end sections may be engaged therewith.

The support or stabilizing assembly 17 is provided for the purpose of supporting or stabilizing the extension assembly 12 and to hold the same in proper position so as to form substantially an extension of the conventional boom structure 10. To this end, it will be noted that the support assembly 17 as shown in Fig. 4 includes a pair of downwardly divergent leg portions 47 and 48 which are preferably formed of tubular stock. Each of these tubular legs 47 and 48 is provided with a notch in its lower end and disposed therein are the extension plates or straps 49 and 59, the parts being connected by welding as indicated at 51 and 52. The lowermost ends of the straps 4-9 and 50 are inwardly angulated as indicated by the reference characters 53 and 54 and these end portions are provided with the apertures 55 and 56 for reception of the pin member 16 previously described which effects the connection between the extension assembly 12 and the support assembly 17. Like the pin 11, suitable cotter pins may be associated with the pin member 16. The arms 20 and 21 of the base section 13 are provided with upstanding lug portions 57 which are apertured to cooperate with the apertured end portions 53 and 54 of the leg extensions 49 and 50 to receive the pin 16 and thus effect connection between the assemblies 12 and 17.

Extending between and rigidly interconnecting the leg members 47 and 48 is a generally triangular shaped plate member 58, this plate member being rigidly connected to the legs preferably by welding. The upper edge of the plate 59 terminates short of the upper ends of the leg members 47 and 48, these upper ends of the leg members being connected together by means of the plate 60 which is welded thereto as at 61 and 62. The plate 66 is provided centrally thereof with an aperture through which the shank 63 of a T-shaped anchor pin is projected and this shank is rigidly secured to the legs 47 and 48 below the plate 60 by means of the welds 64 and 65, thus serving not only to rigidly secure the shank 63 to the assembly but also to provide a further rigidifying connection between the upper ends of the legs 47 and 48. The cross piece 66 of the T-shaped anchor pin is disposed in spaced relation above the upper surface of the plate 60 and disposed on either side thereof and in spaced relation thereto are the upstanding plate members 67 and 68 which may be apertured in the region above the cross piece 66 to permit the insertion of the pin member 69 therethrough in the manner shown. Cotter pins 70 and 71 may be associated with the pin member 69 to retain it in place.

In practice, the pin member 69 is removed when the parts are being assembled and when the extension assembly 12 has been properly assembled, the support assembly 17 is engaged therewith and a length of cable having bights or loops formed at its opposite ends is engaged with the projected end portions of the previously described pin 44 such that the two flights 72 and 73 of this cable are looped about the anchor pin 63. One such bight or eye 74 of this cable is illustrated in Fig. 1 and as shown, once the eye has been engaged with the pin 44, a metallic washer member 75 is placed on the pin and held in place by the cotter pins 76 to retain the bights of the cable in place. A similar length of cable is secured at its opposite ends to suitable lugs, not shown, which are rigidly attached to the conventional boom construction and this cable is looped in its midsection about the anchor pin 63 similar to the previously mentioned cable so as to form the two flight portions 77 and 78. During the engagement of the cables with the anchor pin, the side plate members 67 and 68 serve to retain the cables engaged with the anchor pin and prevent the relatively stiff cables from spreading apart and disengaging therefrom. Of course, the cross piece 66 of the anchor pin also serves to prevent disengagement of the cables from the pm.

These two lengths of cable which extend in opposite directions, one connecting with the pin 44 and the other connecting with the boom and both connected to the anchor pin 63 serve to retain the various component parts of the extension assembly in proper relation and will prevent their disengagement.

The plate member 58 is provided with a substantially centrally disposed opening 79 which is rectangular and vertically elongate and which is disposed on opposite sides thereof with angle iron members whose leg portions 80 and 81 are rigidly attached to the face of the plate 58 as by welding or the like and which have their other legs 82 and 83 projecting outwardly from the plate and apertured substantially medially thereof to receive a pivot pin member 84 having journaled thereon a sheave or pulley 85 in the manner shown most clearly in Figs. 1 and 4. The boom cable 46 is passed through the opening 79 and is trained over the pulley member 85 as will be clearly seen.

I claim:

1. A boom extension comprising an extension assembly composed of three separable sections, and a support assembly for maintaining the extension assembly sections in proper relationship on an associated boom, said extension assembly including a base section adapted to be pivotally connected to the end of a boom, an end section, and a tubular intermediate section telescopically and rotatably received in both the base and end sections and spacing them apart, said support assembly having its lower end connected to said base section and having an anchor post at its upper end, there being first and second cable means connecting said anchor post respectively to said end section and to the associated boom, the first cable means consisting of a length of cable secured at its opposite ends to the end section and passing freely over said anchor post to permit said end section to twist relative to the intermediate and base sections without imparting torsional stresses thereto.

2. A boom extension comprising an extension assembly composed of three separable sections, and a support assembly for maintaining the extension assembly sections in proper relationship on an associated boom, said extension assembly including a base section adapted to be pivotally connected to the end of a boom, an end section, and an intermediate section telescopically received in both the base and end sections and spacing them apart, said support assembly having its lower end connected to said base section and having an anchor post at its upper end, there being first and second cable means connecting said anchor post to said end section and the associated boom, said base section including a pair of mutually convergent arms, a tubular body member secured between the adjacent ends of said arms and having one end thereof disposed between said arms, a stop member secured between said arms and abut-ting said one end of the body member to provide a socket for the reception of said intermediate section, and the free ends of said arms being apertured for the reception of a pin for securing the base section to the associated boom.

3. A boom extension comprising an extension assembly composed of three separable sections, and a support assembly for maintaining the extension assembly sections in proper relationship on an associated boom, said extension assembly including a base section adapted to be pivotally connected to the end of a boom, an end section, and an intermediate section telescopically received in both the base and end sections and spacing them apart, said support assembly having its lower end connected to said base section and having an anchor post at its upper "end, there being first and second cable means connecting said anchor post to said end section and the associated boom, said end section including an elongate tubular member having a longitudinally extending notch formed in one end, a pair of spaced plate members secured within said notch, a pin projecting through said tubular member and said plates, and a pulley journaled on said pin between said plates.

4. A boom extension comprising an extension assembly composed of three separable sections, and a support assembly for maintaining the extension assembly sections in proper relationship on an associated boom, said extension assembly including a base section adapted to be pivotally connected to the end of a boom, an end section, and an intermediate section telescopically received in both the base and end sections and spacing them apart, said support assembly having its lower end connected to said base section and having an anchor post at its upper end, there being first and second cable means connecting said anchor post to said end section and the associated boom, said base section including a pair of mutually convergent arms, a tubular body member secured between the adjacent ends of said arms and having one end thereof disposed between said arms, a stop member secured between said arms and abutting said one end of the body member to provide a socket for the reception of said intermediate section, and the free ends of said arms being apertured for the reception of a pin for securing the base section to the associated boom, said end section including an elongate tubular member having a longitudinally extending notch formed in one end, a pair of spaced plate members secured within said notch, a pin projecting through said tubular member and said plates, and a pulley journaled on said pin between said plates.

5. A boom extension comprising an extension assembly composed of three separable sections, and a support assembly for maintaining the extension assembly sections in proper relationship on an associated boom, said extension assembly including a base section adapted to be pivotally connected to the end of a boom, an end section, and an intermediate section telecopically received in both the base and end sections and spacing them apart, said support assembly having its lower end connected to said base section and having an anchor post at its upper end, there being first and second cable means connecting said anchor post to said end section and the associated boom, said support member including a pair of downwardly diverging legs having extensions at their lower ends for connection to said base section, a connector plate extending between and interconnecting said legs and having a central opening therein, a pulley journaled in said plate opening, said anchor pin being rigidly affixed to the upper ends of said legs.

6. A boom extension comprising an extension assembly composed of three separable sections, and a support assembly for maintaining the extension assembly sections in proper relationship on an associated boom, said extension assembly including a base section adapted to be pivotally connected to the end of a boom, an end section, and an intermediate section telescopically received in both the base and end sections and spacing them apart, said support assembly having its lower end connected to said base section and having an anchor post at its upper end, there being first and second cable means connecting said anchor post to said end section and the associated boom, said support member including a pair of downwardly diverging legs having extensions at their lower ends for connection to said base section, a connector plate extending between and interconnecting said and having a central opening therein, a pulley journaled in said plate opening, said anchor pin being rigidly afiixed to the upper ends of said legs, said end section including an elongate tubular member having a longitudinally extending notch formed in one end, a pair of spaced plate members secured within said notch, a pin projecting through said tubular member and said plates, and a pulley journaled on said pin between said plates.

7. A boom extension comprising an extension assembly composed of three separable sections, and a support assembly for maintaining the extension assembly sections in proper relationship on an associated boom, said extension assembly including a base section adapted to be pivotally connected to the end of a boom, an end section, and an intermediate section telescopically received in both the base and end sections and spacing them apart, said support assembly having its lower end connectedto said base section and having an anchor post at its upper end, there being first and second cable means connecting said anchor post to said end section and the associated boom, said support member including a pair of downwardly diverging legs having extensions at their lower ends for connection to said base section, a connector plate extending between and interconnecting said legs and having a central opening therein, a pulley journaled in said plate opening, said anchor pin being rigidly af fixed to the upper ends of said legs, said base section including a pair of mutually convergent arms, a tubular body member secured between the adjacent ends of said arms and having one end thereof disposed between said arms, a stop member secured between said arms and abutting said one end of the body member to provide a socket 'for the reception of said intermediate section, and the free ends of said arms being apertured for the reception of a pin for securing the base section to the associated boom, said end section including an elongate tubular member having a longitudinally extending notch formed in one end, a pair of spaced plate members secured within said notch, a pin projecting through said tubular member and said plates, and a pulley journaled on said pin between said plates.

References Cited in the file of this patent UNITED STATES PATENTS 1,920,370 Forsythe et a1. Aug. 1, 1933 1,941,952 Nickles Jan. 2, 1934 2,574,409 North Nov. 6, 1951 FOREIGN PATENTS 748,027 France June 27, 1933 

